Loading ...
Sorry, an error occurred while loading the content.

Re: Is there something wrong with my optics

Expand Messages
  • Julio César Monje
    Kurt, English is not my native language and I m afraid, by the time I received the reply, that it came from Taiwan, so maybe the exact meaning is a little bit
    Message 1 of 100 , Mar 5, 2007
    • 0 Attachment
      Kurt,

      English is not my native language and I'm afraid, by the time I
      received the reply, that it came from Taiwan, so maybe the exact
      meaning is a little bit confusing.

      Anyway I understood same idea as in your re-wording but I'm still
      wondering why this effect is not so apparent in other air-spaced
      triplets also designed by TMB, like APM/TMB. Maybe screws in FLT110
      design protrude some more in the light path than other brands
      designs. Also I don't understand reason to use screws as spacers
      instead of rings as usually we could find in eyepieces. Do you have
      some explanation?

      An aperture mask could be a good solution to get rid of this effect.
      What's your opinion? I'm anxiously waiting for WO commentaries on
      this suggestion.

      Thanks.


      --- In William-Optics@yahoogroups.com, Kurt Friedrich
      <kurt_friedrich@...> wrote:
      >
      > I am not sure I exactly understand this quote from WO.
      > Please see if my re-wording is correct.
      >
      > The spikes are from the edges of two sets of 3
      > adjustment screws. (total of 6 screws). Unlike oil
      > based triplets, where the spacing between the 3 lenses
      > is maintained correctly by the thin film of oil, with
      > air space triplets, the spacing between the lenses
      > must be set precisely, and this is done with the two
      > sets of adjustment screws in the lens cell, and they
      > are spaced at 120 degree around the lens cell. The tip
      > of each of these 6 screws projects very slightly
      > between 2 lens surfaces, to set and maintain their
      > spacing.
      >
      > If I got that right, it explains why we have seen this
      > effect in other brands of scopes, and why it is not
      > there with some famous oil spaced scopes such as from
      > AP and TEC. I know the current designs from AP are
      > air spaced, I will ask Roland how he maintains the
      > spacing.
      >
      > Kurt
      >
      > --- Julio César Monje <JULIO__CESAR@...>
      > wrote:
      >
      > > I've just received reply from WO technical support
      > > about "dark
      > > spikes" as follows:
      > >
      > > quote
      > >
      > > The spikes is from the 3 edge of 120 degree per. two
      > > adjustment
      > > screws (the reflection of tip on 6 screws) the
      > > design is not like the
      > > oil spaced without any reflection in between 3
      > > lenses, our design is
      > > air spaced, we have 2 space reflection in between 3
      > > lenses (total 6
      > > surface coating on lens in cell).
      > > it's not defective, all new FLT 110 are the same,
      > > for maximum
      > > performance of color correction it can not be
      > > changed without dark
      > > spikes on the bright star.
      > >
      > > unquote
      > >
      > > As I suspected, there's no defective optics but some
      > > effect caused by
      > > optical design. It seems to be located in the
      > > triplet air-spacing but
      > > I've never seen this effect in pictures of other
      > > brand scopes. What's
      > > your opinion? Should I return my scope or keep it? I
      > > like a lot
      > > visual performance.
      > >
      > > Thanks everybody for the help.
      > >
      > >
      >
      >
      >
      >
      >
      ______________________________________________________________________
      ______________
      > Don't pick lemons.
      > See all the new 2007 cars at Yahoo! Autos.
      > http://autos.yahoo.com/new_cars.html
      >
    • Eric Faust
      The turned edge would not cause the dark lanes , but it would make them clearly visible by causing the bright smear of light around the bright star. Were the
      Message 100 of 100 , Mar 19, 2007
      • 0 Attachment
        The turned edge would not cause the "dark lanes", but it would make
        them clearly visible by causing the bright smear of light around the
        bright star. Were the star a perfect airey disk, the only visible
        effect of the spacers would be faint diffraction spikes. I'm not
        saying that this is or isn't a problem on any or all FLT-132's.


        --- In William-Optics@yahoogroups.com, <danjanos@...> wrote:
        >
        > It seems the cause of the dark lanes is mechanical whether spacers
        or
        screws in the optical path. When you stretch an image the dark lanes
        become more prominent as do a brightness on the sides of each of the
        dark lanes. This brightening is symptomatic of something in the
        optical
        path similar to a reflector and it's diffraction spike caused from
        the
        secondary holder.
        > a turned edge will not cause a dark lane . It creates an uneven
        brightness around stars and is especially notable on brighter stars.
        > I look forward to your rationale.
        >
      Your message has been successfully submitted and would be delivered to recipients shortly.